Michael Snoyman and I were discussing the need for beta releases of Yesod and he encourage me to post this to the cafe. Beta releases could be built into the hackage system. However, this can be viewed as a more general problem of distributing multiple versions of code (stable vs. experimental, forks, etc). This is a problem that has been largely solved by version control, but in this instance just needs some integration with an installer system.<div>

<div><div><br></div><div>In the ruby world there is a tool called bundler that is now the standard installer- basically bundler combined with rubygems it is like cabal combined with hackage. In addition to referencing a published library version, with bundler one can reference a git repository, and even reference a particular branch or revision. Essentially with beta releases you are trying to release multiple branches of your repository. This is also very useful for dealing with multiple forks of a package. If I have problems with a package I can look at the github repo and look for forks with bug fixes, and then point the Gemfile (cabal file) to that repo. The repo must have a gemspec (cabal file).</div>

<div><br></div><div>Essentially this removes the step of the code writer of needing to edit the cabal file or publish to hackage. This is good because many code writers do not want to publish their minor variations of packages on hackage or do not want to publish new packages that they feel are of low quality. This is also good from the perspective of the code user- I normally don&#39;t want to see minor variations on hackage. If I am interested in minor variations I will go to the github repo and look at the different branches and forks where it will be clear to me what the difference is- it would be difficult to accurately portray this information on hackage.</div>

<div><br></div><div>Productivity in modern programming is largely about code re-use, and I only see this as becoming more important. Type safety and Cabal do a great job facilitating code re-use. I think we can make cabal even more useful here. Has this ability been discussed before for cabal? t would be great if it could at least be worked on for the next Google Summer of Code.</div>

</div></div><div><br></div><div>Sorry if I offended anyone by exclusively mentioning git, but that is the only version control system used by Rubyists :)</div>